esig Posted October 21, 2014 Posted October 21, 2014 I have two substances 20.0g 1M CuSO4 and 1g Fe. I have found the moles and have calculated this for other reactions but what I am not sure of is if weather i should use both substances for moles in the equation or just one, and if I should use just one then witch one? The equation in -q/1000/m I have 0,00002 moles CuSO4 and 0,018 moles Fe
studiot Posted October 21, 2014 Posted October 21, 2014 (edited) Well let's see 1g of Fe = 1/55.85 moles 20g of CuSO4 = 20/159.62 moles So which one will be completely used up by the displacement reaction and which one will have some reactant left over? Do you know what reaction takes place? edit: reading this again did you mean 20g of 1molar solution of copper sulphate? The end question will be the same, which one is used up, but the figures will be different. Have you seen this http://www.youtube.com/watch?v=KmhD8BmEFIo Finally this is a displacement reaction so what displaces what? When reporting the heat of reaction I would say __kJ/mole of ___displaced Edited October 21, 2014 by studiot
esig Posted October 21, 2014 Author Posted October 21, 2014 yes I did mean that I have 20,0 g of 1 Molar solution of copper sulfate, and the Iron was powder and dissolved in the solution, the video was very interesting though. The answer is only supposed to be in kJ/mole nothing is mentioned of displacement. I have found delta t, balanced all the equations and found kj/mol for all the reactions exept for this one since.
hypervalent_iodine Posted October 22, 2014 Posted October 22, 2014 Do you mean 20mL of the CuSO4 solution? As with what studiot has said, you need to work out which of these is the limiting reagent and use that value. Don't worry about the "of ____ displaced," this is not necessary. Studiot is referring to the type of reaction you have, which is a displacement reaction.
esig Posted October 22, 2014 Author Posted October 22, 2014 So once I find the limiting reactant that will tell me witch I should use? And to be clear I should use the limiting reactant in the equation?
hypervalent_iodine Posted October 22, 2014 Posted October 22, 2014 First question: yes. Second question: I'm not sure what you mean by this exactly. You use the limiting reagent to calculate how many moles have reacted. You need this value to calculate delta H.
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